U.S. patent application number 10/748059 was filed with the patent office on 2005-07-07 for urethral stent reducer.
This patent application is currently assigned to Ethicon, Inc.. Invention is credited to Contiliano, Joseph H., Overaker, David W., Tenhuisen, Kevor.
Application Number | 20050149162 10/748059 |
Document ID | / |
Family ID | 34574758 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050149162 |
Kind Code |
A1 |
Tenhuisen, Kevor ; et
al. |
July 7, 2005 |
Urethral stent reducer
Abstract
An apparatus for compressing a coiled stent having at least one
protrusion, such as an enlarged coil disposed at the end of the
stent, has a mandrel insertable into a lumen of the stent for
holding the stent by friction and a coil compressor coupled to the
mandrel. The mandrel is rotatable on an axis relative to the coil
compressor and the coil compressor has a tab extending therefrom
towards the mandrel. A stent is placed on the mandrel with the
enlarged coil extending toward the coil compressor. The tab presses
the enlarged coil inwardly toward the lumen of the stent when the
mandrel is rotated relative to the coil compressor.
Inventors: |
Tenhuisen, Kevor; (Randolph,
NJ) ; Contiliano, Joseph H.; (Stewartsville, NJ)
; Overaker, David W.; (Annandale, NJ) |
Correspondence
Address: |
MCCARTER & ENGLISH, LLP
FOUR GATEWAY CENTER
100 MULBERRY STREET
NEWARK
NJ
07102
US
|
Assignee: |
Ethicon, Inc.
|
Family ID: |
34574758 |
Appl. No.: |
10/748059 |
Filed: |
December 29, 2003 |
Current U.S.
Class: |
623/1.11 |
Current CPC
Class: |
A61M 27/008 20130101;
Y10T 29/49927 20150115; A61F 2/9526 20200501; A61F 2002/047
20130101; A61M 25/01 20130101; A61F 2/9522 20200501 |
Class at
Publication: |
623/001.11 |
International
Class: |
A61F 002/06 |
Claims
We claim:
1. An apparatus for compressing a stent having at least one
protrusion, comprising: a mandrel insertable into a lumen of the
stent for holding the stent; a protrusion compressor coupled to
said mandrel, said mandrel rotatable relative to said protrusion
compressor, said protrusion compressor having a tab extending
therefrom towards said mandrel, said tab pressing the at least one
protrusion of the stent inwardly toward the lumen of the stent when
said mandrel is rotated relative to said protrusion compressor.
2. The apparatus of claim 1, wherein said mandrel extends through
said protrusion compressor coaxially.
3. The apparatus of claim 2, further comprising a knob disposed on
an end of said mandrel to aid in turning said mandrel and for
retaining said protrusion compressor on said mandrel.
4. The apparatus of claim 3, wherein said mandrel has a stent
fixation zone with an outer diameter approximating the interior
diameter of at least a portion of the lumen of the stent and
frictionally engaging the stent when the stent is placed on the
mandrel over the stent retention zone.
5. The apparatus of claim 4, wherein said mandrel has a tapered end
leading to said stent retention zone, said tapered end aiding in
inserting the mandrel into the lumen of the stent and sliding the
stent on to the stent retention zone.
6. The apparatus of claim 4, wherein said protrusion compressor is
captured between said knob and said stent retention zone.
7. The apparatus of claim 6, wherein said protrusion compressor has
a grip portion with a hub and a collar, said collar coaxially
received on said hub and having said tab extending therefrom at a
distal end thereof, said collar restrained from rotating relative
to said grip portion by a pin extending there through and into an
elongated slot in said hub, said slot and pin constraining the
collar to telescopic movement on said hub along a length of travel
limited by said slot and defining a retracted position and a
deployed position for said tab.
8. The apparatus of claim 7, wherein said collar has a flange
extending outwardly therefrom for a user to grip said collar to aid
in deployment and retraction of said tab.
9. The apparatus of claim 8, wherein said grip portion has a hollow
post extending from said hub, said post having a relief slot on a
distal end thereof, said relief slot positioned on said post to
align with said tab when said tab is in the deployed position, said
tab capturing the at least one protrusion of the stent between said
tab and said relief slot when said apparatus compresses the at
least one protrusion.
10. The apparatus of claim 9, further including a ball and detent
interface disposed between said grip portion and said collar, said
ball and detent interface controlling the relative rotation between
said grip portion and said collar.
11. The apparatus of claim 10, wherein the at least one protrusion
of the stent is at least one enlarged coil disposed at an end of
the stent, said apparatus pressing the enlarged coil inwardly by
pushing said collar portion forward to the deployed position to
capture said enlarged coil between said tab and said relief slot
and turning the knob and the mandrel relative to said protrusion
compressor.
12. The apparatus of claim 11, further including a sleeve extending
from said collar distal to said flange, said tab extending from
said sleeve.
13. An apparatus for compressing a coiled stent having at least one
external protuberance, comprising: means for holding the stent;
means for compressing the at least one external protuberance, said
means for compressing being rotatably coupled to said means for
holding, such that relative rotation thereof compresses the at
least one protuberance, said means for compressing acting on the
stent by exerting a force perpendicular to an axis of the
stent.
14. The apparatus of claim 13, further comprising, means for
gripping said means for holding the stent to aid in rotating said
means for holding relative to said means for compressing.
15. The apparatus of claim 14, further comprising, means for
gripping said means for compressing the stent.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to apparatus used for
compressing a coiled stent and more particularly, for compressing a
specific end portion of a stent prior to insertion either into an
insertion apparatus or directly within the body.
BACKGROUND OF THE INVENTION
[0002] Lower urinary tract symptoms (LUTS), common among older men,
include a variety of disorders that can lead to urinary retention
and complications resulting from retention. Some of the conditions
falling under a LUTS diagnosis include an enlarged prostate, BPH,
and bladder outlet obstruction.
[0003] The constriction of the urethra due to prostatic enlargement
can be treated by the implantation of a prostatic urethral stent.
The stent serves to hold the prostatic urethra open to allow
urination. This is typically an interim solution used before or
after corrective treatment, e.g., a stent may be implanted after
radiation treatments, thermal therapy or cryosurgery to keep the
urethra open while post-treatment edema subsides. In some
instances, a stent may be implanted as a primary treatment.
[0004] Generally, urethral stents are tubular in shape and may be
in the form of a solid tube, coiled wire, ribbon or mesh, or formed
from braided filaments. Coiled stents may be designed to have at
least a portion thereof with outer diameter equal to or larger than
the average urethral lumen diameter, such that when expanded, the
stent frictionally engages the urethra into which it has been
inserted. The larger diameter coils of such stents need to be
radially compressed prior to insertion into a stent delivery
system, e.g., a catheter sheath, or within the urethra. After being
positioned in the urethra, urethral stents are radially expanded
into their final shape, typically by thermal or mechanical means,
or, in the case of self-expanding stents, allowed to elastically
expand when a sheath or other restraining means is removed.
[0005] Brenneman et al. (U.S. Pat. No. 5,160,341) disclose a device
including a retractable sheath surrounding a rotatable rod
journaled in a stationary tubular bushing. One end of the stent is
mounted on the rod while the other end of the stent is fixed to the
bushing so that relative rotation of the rod and bushing compresses
the entire stent by coiling it more tightly. After insertion within
the body, the rod and bushing are then rotated in the opposite
direction to uncoil the stent to its original diameter. A shearing
sleeve with a shearing edge is advanced between the rod and bushing
to sever the stent from its attachment to the bushing and the
rod.
[0006] In the above device, both ends of the stent are used to
engage the urethra and the diameter along the entire stent length
is reduced. Reduction of stent diameter results in a concomitant
increase in length in the reduced region. Reduction of stent
diameter along the entire stent length will therefore result in
significant length increases upon diameter reduction, sizing,
bunching, and consequent placement issues within the anatomy. In
some coil stent designs, only an end portion of the stent has a
varying diameter. It is undesirable, particularly with polymer
stents, to expose a stent to unnecessary forces due to risk of
plastic deformation or creep. There are also risks associated with
introducing a shearing sleeve with shearing edge within the urethra
e.g. breakage, contamination and/or injury. In addition, the cut
ends of the stent are sharp and pose a risk of penetrating the
urethra.
[0007] Yachia et al. (U.S. Pat. No. 5,246,445) disclose stents with
non-uniform windings such that one or more coils along the length
of the stent bulge out circumferentially. An apparatus is disclosed
which fixes either end of the stent and through torquing action,
radially compresses the bulges. Here again, the entire length of
the stent is reduced by rotating the ends of the helical spiral in
opposite directions. A small hook, ring, or ball is provided at
each end of the stent for grasping it. These features diminish
uninterrupted flow capacity through the stent and increase the
complexity of manufacture. Counter-rotation is required to release
the stent.
[0008] Limon (U.S. Pat. No. 5,476,505) discloses a stent delivery
system including a catheter formed from coaxially arranged inner
and outer flexible shafts, the distal ends of which have slots or
apertures to engage the ends of a coiled stent. The entire length
of the stent is effected by inducing tighter coiling. The device is
counter-rotated to expand and release the stent.
[0009] It would therefore be desirable to be able to radially
compress selected regions of a coiled stent without compressing the
entire stent. Such a device can be used to facilitate placement of
the stent either within a secondary insertion tool or directly
within the body.
SUMMARY OF THE INVENTION
[0010] The limitations of prior art apparatus for compressing
stents are overcome by the present invention which includes an
apparatus for compressing a coiled stent having at least one
protrusion. The apparatus has a mandrel insertable into a lumen of
the stent for holding the stent and a coil compressor coupled to
the mandrel. The mandrel is rotatable on an axis relative to the
coil compressor and the coil compressor has a tab extending
therefrom towards the mandrel. The tab presses the protrusion of
the stent inwardly toward the lumen of the stent when the mandrel
is rotated relative to the coil compressor.
BRIEF DESCRIPTION OF THE FIGURES
[0011] The novel features of the present invention will be more
readily apparent upon reading the following description in
conjunction with the drawings in which like elements in different
figures are identified by the same reference numeral and
wherein:
[0012] FIG. 1 is an exploded view of a stent reducer in accordance
with an embodiment of the present invention;
[0013] FIG. 2 is an exploded view of a latch assembly of the stent
reducer of FIG. 1;
[0014] FIG. 3 is a perspective view of the latch assembly of FIG.
2;
[0015] FIG. 4 is a partially exploded view of the latch assembly
and mandrel knob of the stent reducer of FIGS. 1-3;
[0016] FIG. 5 is a perspective view of the stent reducer of FIGS.
1-4;
[0017] FIG. 6 is a perspective view of the stent reducer device of
FIGS. 1-5 with a stent on the mandrel;
[0018] FIG. 7 is a partial cross-sectional view of the stent
reducer of FIGS. 1-6 taken along section line VII-VII looking in
the direction of the arrows and with a stent on the mandrel prior
to reduction of the distal stent diameter;
[0019] FIG. 8 is a cross-sectional view like FIG. 7, but after
reduction of the distal stent diameter;
[0020] FIG. 9 is a cross-sectional view like FIG. 8 as the stent is
being loaded into a sheath; and
[0021] FIG. 10 is a cross-sectional view of the stent loaded into
the sheath.
DETAILED DESCRIPTION OF THE INVENTION
[0022] FIGS. 1 through 9 show a stent reducer 10 for use in
radially compressing selected larger diameter, radially-expanded
coils 86 (See FIG. 6) of a coiled stent 80 without radially
compressing the entire stent along its length. Stent 80 has a
generally cylindrical coil shape, such as the stent described in
U.S. patent application Ser. No. 10/602,338, entitled
"Biodegradable stent", assigned to Ethicon Incorporated, filed Jun.
24, 2003, and incorporated herein by reference.
[0023] The stent 80 has a distal end 84 and a proximal end 82. Note
that "proximal" and "distal" are reversed from the directionality
of the stent reducer 10, because the convention applied to the
stent 80 is relative to the bladder of the patient in which the
stent 80 is placed. The diameter of the distal end 84 is greater
than the remainder of the stent 80 due to radially expanded coil
86. While more than one complete turn of the coiled stent 80 is
enlarged in FIG. 6, less than or greater than one complete turn of
the stent 80 may be enlarged.
[0024] As shown in FIG. 1, stent reducer 10 has a mandrel 20 with a
tapering distal end 22 which facilitates the insertion of the
mandrel 20 into the lumen 81 (See FIG. 6) of the coiled stent 80, a
proximal end 24 and a stent fixation zone 26. The diameter of the
stent fixation zone 26 is the same as, or slightly larger than, the
inner diameter of at least some portion of the stent 80, so that an
interference fit is established between stent 80 and stent fixation
zone 26 when the mandrel 20 is inserted into the stent 80.
Preferably, the stent 80 can be rotated on the mandrel manually
with minimal resistance. Since the stent 80 has a spiral shape,
manual rotation of the stent 80 on the mandrel 20 can serve to
advance the stent 80 over the mandrel 20 in threaded fashion. The
surface of the stent fixation zone 26 may be textured to enhance
the interference fit/thread-like interaction established between
the stent 80 and stent fixation zone 26. The mandrel 20 may be
one-piece or in a plurality of modular sections to accommodate
various stent 80 sizes. The modular sections can be connected by
conventional means, e.g., threads, snap-fit coupling, etc. A latch
assembly 30 for compressing protrusions in the stent 80, such as
expanded coils 86, slips over the proximal end 24 of the mandrel
20, as does mandrel knob 60.
[0025] FIG. 2 shows an exploded view of latch assembly 30, which
includes latch knob 40 and latch collar 50. The latch knob 40 has a
grip portion 42, a hub portion 44 with a slot 45, and a post
portion 46 with a relief 47. The latch knob 40 has an axial
cannulation 41 into which the post 64 of mandrel knob 60 inserts
and which also allows the mandrel 20 to extend through the latch
knob 40. The latch knob 40 has ball plunger detents 49 on its
proximal end (see FIG. 4). Latch collar 50 has a flange 52 against
which the fingers of a user may press to control the position
thereof. A pin 57 extends through hole 58 after the latch collar 50
is slidably and coaxially slipped onto the hub portion 44, the end
of the pin 57 being accommodated in slot 45 and retaining the latch
collar 50 on the latch knob 40 while permitting relative movement
to the extent of the length of the slot 45. The latch collar 50 has
a stepped internal bore 59 having internal dimensions approximating
the external dimensions of the hub and post portions 44, 46 of the
latch knob 40. A sleeve 54 extends from the flange 52 and has a
distal tab 56 for contacting and compressing the stent 80.
[0026] As shown in FIG. 3, when assembled to form latch assembly
30, tab 56 overhangs relief 47. The length of slot 45 limits the
range of axial motion of latch knob 40 in the distal direction to
the point where tab 56 at least partially overhangs relief 47.
[0027] FIG. 4 shows mandrel knob 60, which has a grip portion 62
with a mandrel bore 65 for receiving proximal end 24 of mandrel 20
therein. The mandrel 20 is retained by a set screw (not shown)
inserted into a threaded bore 66 and bearing upon the proximal end
24 thereof. A ball plunger 68 or similar spring-tape resilient
member (not shown) is received within mating bore 69. Detents 49
are provided on a proximal surface 43 of latch knob 40 and receive
the ball plunger 68 therein to control the axial rotation of
mandrel knob 60 and mandrel 20 relative to the latch knob 40. FIG.
4 shows the latch knob 40 withdrawn to a proximal position wherein
the tab 56 is retracted from relief 47.
[0028] FIG. 5 shows the fully assembled stent reducer 10. The
diameter of stent fixation zone 26 is approximately the same as the
diameter of post portion 46. This prevents latch assembly 30 from
sliding off of the mandrel 20.
[0029] FIG. 6 shows a stent 80 in position on the mandrel 20 of
stent reducer 10 prior to compression of radially expanded coils 86
on the distal end 84 of the stent 80.
[0030] FIG. 7 through 10 show cross-sectional views of the stent
reducer 10 and how it is used to reduce the diameter of the
enlarged coils 86 at the distal end 84 of the stent 80, and load
the stent 80 into a sheath 90. In FIG. 7, the mandrel 20 is
inserted into the lumen of stent 80. The enlarged coils 86 of stent
80 distal end 84 are of a larger diameter than the remainder of the
stent 80 and extend beyond the stent fixation zone 26 in the
proximal direction. The latch collar 50 is positioned proximally on
the latch knob 40 such that the tab 56 is retracted to a position
removed from relief 47.
[0031] FIG. 8 shows the reduced distal end 84 of the stent 80
resulting from pushing the latch collar 50 forward, such that the
tab 56 extends over an outer surface of the enlarged coil 86,
capturing it between the tab 56 and the relief 47.
[0032] The user then grasps the mandrel knob 60 and the latch knob
40 and axially rotates the mandrel knob 60 relative to the latch
knob 40 to reduce the diameter of the distal end 84 of stent 80.
The ball plunger 68 and ball plunger detents 49 (FIG. 4) provide
controlled relative rotation defining discrete tightening steps to
avoid overrotation of stent 80. Once the outer diameter of the
enlarged coils 86 are reduced, the stent 80 may be inserted into
the sheath 90. When the stent 80 is fully inserted into sheath 90
i.e., beyond sheath proximal end 92, the user pulls the latch
collar 50 proximally, releasing its hold on the enlarged coils 86
and permitting them to expand with the sheath exerting a frictional
grip thereon. The mandrel 20 is then removed from the stent lumen
81, leaving the stent 80 disposed (loaded) in the sheath 90. FIG.
10 shows a stent 80 in a sheath 90 after removal of the mandrel
20.
* * * * *